ght Patents
XXIV. Hints on Propeller Construction
XXV. New Motors and Devices
XXVI. Monoplanes, Triplanes, Multiplanes
XXVII. Records of Various Kinds

FLYING MACHINES: CONSTRUCTION and OPERATION

CHAPTER I. EVOLUTION OF TWO-SURFACE FLYING MACHINE.

By Octave Chanute.

I am asked to set forth the development of the "two-surface" type of
flying machine which is now used with modifications by Wright Brothers,
Farman, [1] Delagrange, Herring and others.

This type originated with Mr. F. H. Wenham, who patented it in
England in 1866 (No. 1571), taking out provisional papers only. In the
abridgment of British patent Aeronautical Specifications (1893) it is
described as follows:

"Two or more aeroplanes are arranged one above the other, and support a
framework or car containing the motive power. The aeroplanes are made of
silk or canvas stretched on a frame by wooden rods or steel ribs. When
manual power is employed the body is placed horizontally, and oars or
propellers are actuated by the arms or legs.

"A start may be obtained by lowering the legs and running down hill or
the machine may be started from a moving carriage. One or more screw
propellers may be applied for propelling when steam power is employed."

On June 27, 1866, Mr. Wenham read before the "Aeronautical Society of
Great Britain," then recently organized, the ablest paper ever presented
to that society, and thereby breathed into it a spirit which has
continued to this day. In this paper he described his observations of
birds, discussed the laws governing flight as to the surfaces and power
required both with wings and screws, and he then gave an account of his
own experiments with models and with aeroplanes of sufficient size to
carry the weight of a man.

Second Wenham Aeroplane.

His second aeroplane was sixteen feet from tip to tip. A trussed spar at
the bottom carried six superposed bands of thin holland fabric fifteen
inches wide, connected with vertical webs of holland two feet apart,
thus virtually giving a length of wing of ninety-six feet and one
hundred and twenty square feet of supporting surface. The man was placed
horizontally on a base board beneath the spar. This apparatus when tried
in the wind was found to be unmanageable by reason of the fluttering
motions of the fabric, which was insufficiently stiffened with crinoline
steel, but Mr. Wenham pointed out that this in no way invalidated
the prin